Tire-pressure tester



g H. E. MCNATT TIRE PRESSURE TESTER- Feb. 22,1927. 1,618,211

Filed June 291 1.925

ff@ 3 if? .4

"f l y 1111 M amm.

' l will Y appreciable Wear.

' a certain pressure noiviER E. MENATT, or ENGLEWOOD, MISSOURI, nss'rcuor.- To Hiivrsnnr As TRUSTEE..

` This-invention relates to fluid `pressure testers and is adapted for use particularly with automobile tireswone of theobjects of 1 the invention'is to produce a pressure tester Which lwill lbe initially set to operate Yat a predetermined minimum; pressure and Will register When a tire is atfthe minimum pr`es sure Vor above,- either through an audible signal or through the sense of touch as Will Ahereinafter appear.l Y

VAnotherobject is to prlduceV a pressure tester of economical construction having vno movable parte subject to deterioration'or A Afurther object is to produce al pressure tester provided with means whereby the minimum pressure at which the device Will' be operated may be adjusted at the factory,

A, that is all parts of the testers are standard,

the testers varying only in the setting of release opening described hereinbeloiv'.v iE v f A still further object is to produce apressure tester (if Strong, durable, eiiicient and inexpensive construction; and iii order that it may `be fully understood, reference is to be liadtofthe accompanying drawing, in Which:-' V

` Figure l'FV is an elevation of thej rear side otl a pressure tester embodying the invenv tion. l Y

Figure 2 is an elevation of the operative face ofthe tester. f

Figure 3 is a Section on the lineIII-II of Figure l;

`Fgure 4; is a side elevation of .a tester embodying the invention. y

Figure l5 is an enlarged broken sectional view to show a slightly modified diaphragm construction in Which the diaphragm is provided With a pressureexhaust opening.

In the said drawing, Where like reference characters identify corresponding parts in Vall ory theligures, l represents a cylin drical metallic casing of any convenient or desirable diameter, said casing being formed integrally With an outwardly boivedjclosure forming a conical protuberance l. rlhe central portion of the cone is pressed inwardly.`

to form a circular recess 2` in which is centrally located a valve operating stud .3, having its Jface substantially flush-With the mar-A Athe stud 3 to open the valve by pressing on TIRE-'PRESSURE TESTER.

f1 "App'iicationialea June 29, 1325. seriai in.` 40,464.

-the spring-advanced core. The face ofthe stud 3 is formed witha circular fair-inlet" opening l ott center with respect to thestud in order that the valve core stem shalt not impinge ony and' seal `or partially seal the opening-it being notedthat Vthe opening tapers,V increasing in diameter inteiiorly to4 oiier greater resistance to the' accidental ventry of dust or Idirt-into theV casing and to insure the blowing inwardly of any 'dirt which may enter the opening. flhe'bottoniv of the recess 2 is provided ivithla 'Wa'sherf toil air-tight sealing valve .stem as coinnion inthe-art. j

The face l?1 otthe casing ata-point iiiproximity to the `ine-rgin is foi-med* With a circular recess 6 having a 'taperedopeiiing 7, increasing in diameter exteriorly so that any` dust or -dirt Within the Ycasingv lWhichmay enter the opening shall be bloivn out by the current oij' air set up Within the casing asvivill hereinafter appear. Mounted inthe recess vadjacent the'opening is van eccentric;- head rivet or screw 8 havingv a lug 8n Whichin'ay beset so Vthat ,the head, lmore ,or-'less overlapsl the opening A7, or 'mayentirely engagement with "the close the opening. In the use of the device,"

it Yis to be understood that the' air' fromA the tire enters the kcajsii'ig i through"` the y epeningd and exits through the opening 7,

therelation 'of the* areas of the' openings to" each other y,f ov'ernin'gV the inininiiu'n operative pressure necessary for theopcratioii of a diaphragm beloiv-described- It has been found that devices made in accordance with the invent-ion in Which the exit lopening 7 is entirely closed by the eccentric rivet 8 and its lug 8', or in which the opening is entirely omitted, are operative for a predetermined pressure. As a matter of manufacturing convenience it` may `be desirable to make all devices Without an exit opening and then test each device and niark it With the registered pressure, or to make all the devicesv Without an outlet opening and then through a series of experiments ldetermine the area of an opening or seriesV of openings to secureregistration at a pre@v determined pressure.

-Within thev casing and snugly Washer 9 of any suitable relatively non-compressible -material, and resting on Y said v tting against the inside face of the same is a ring iio l' in position a second ring washer 11 is inserted. v

. Fitting upon the washer 11 is a metallic closure plate 12 bowed inwardly to such a point as to provide a stop to prevent the diaphragm from being forced too tar beyond center where it might remain and be thus inoperative, said plate being of suiiicient rigidity to close the back of the casing- The plate 12 is formed with a plurality of openings 13 so that the air back of the dlaphragm shall not be compressed. The closure 12, the washers 9 and 11, and the diaphragm 10 are tightly clamped in posi tion by crimping or rolling the edge 14 of down upon the back of the plateV the casing 12, as illustrated.

In the'operation of the device the operator.

places the tester so that the recess 2 receives the valve stem. Now by pressing downwardly on the casing the stud 3 is'caused to open the valve and the air in the tire rushes into the casing 1 through the opening 4. If

the tire contains sufficient air pressure toV eiectthe snapping or pressing rearwardly of the diaphragm 10, said diaphragm will strike an appreciable blow against the closure `plate 12 or will itself snap or pop, and this fact will be registered to the driver either through the sense of touch in his iinger tips, or by the audible sound of the con tact between the diaphragm and the inner face of the closure 12, or by the flexing or snapping of the diaphragm itself.

From the above description, it will be apparent that I have produced a pressure tester possessing all ot the features of advantagepointed out as desirable and while I have described and claimed the preferred embodiment of the same, I reserve the right to make all changes properly falling within the spirit and scope'of the appended claims.

I claim:

1. kIn a pressure tester, a casing closed at one of its ends and formed'with a valve engaging recess and valve operating lug, said casing having inlet and outlet openings,

a diaphragm mounted in the casing, and av closure plate rearwardly 0i the diaphragm and adapted to be struck thereby. f

2. vIn a pressure tester, Va casing closed at one of its ends and formed with a valve engaging recess and valve operating lug, said casing having inlet and outlet openings, means for varying the relative area ot said openings, adiaphragm mounted in the casing, and a closure plate rearwardly of the diaphragm and adapted to be struck thereby A 3.. In a pressure tester, a casing, a diaphragm in saidA casing, and means on said casing for engaging and opening a valve; said casing being formed with a pressure inlet opening at one side of thediaphragm, and a second unimpeded opening for eX- hausting air entering through said inlet opening.

4. In a pressure tester, a casing closed'at one of its ends and formed with a valve engaging recess and valve operating lug, said lug` being provided with an inlet opening,

a diaphragm mounted in the casing and nor-- mallyY Lbowed inwardlyY toward the inlet opening, and a protecting member for said diaphragm, said member being secured in the end of the casing opposite v'its inlet provided closed end to guard the diaphragm against accidentalcontact by theY operatorV of the device.

. In witnessv whereof VI hereunto aiiix my signature.

HOMER n. MCNATT. Y 

